Shellfish predator screens are composed of sheets of plastic mesh screening. The mesh screening has been utilized extensively by the hard clam (Mercenaria mercenaria) industry to prevent predation from fish and crustaceans. The screens are placed over juvenile shellfish beds and anchored in place by rebar and lead line. The anchors are pressed into the bottom sediments to the extent that the mesh rests immediately above the bottom. The protective screening remains in place until the clams grow beyond a size susceptible to predation. The mesh screening is successful in eliminating predation but quickly becomes fouled by a variety of indigenous seaweed species. Some seaweed species attach to the plastic mesh while others simply settle on top of the screen. The bio-fouling prevents the siphons of the juvenile clams from extending into the water column, causing the clams to suffocate.
Presently, the hard clamming industry reduces the amount of bio-fouling by manually scraping the top of the screens with a metal rod fitted with a loop of rebar at one end. The rebar is covered with PVC tubing or rubber garden hose to prevent against damage of the mesh screening. The screens are cleaned by a person operating from a small skif or wading in the water. The present cleaning technique is extremely labor intensive (one person can clean about six screens per hour) and can only be utilized during low tide. Typically, each screen must be cleaned every 10 to 14 days.
Accordingly, to increase the production efficiency of shellfish aquaculture, and in particular the hard clam industry, there is a need for more efficient techniques and/or devices to clean the protective mesh screens. Such techniques and/or devices should decrease the cleaning time per screen while at the same time reducing the amount of labor needed for cleaning. Additionally, it is desirable to employ a cleaning technique that can be utilized during any phase of the tide.